"If necessary, it should have made efforts to draw support from the private sector and use public diplomacy to promote those issues and persuade the US and the international community over the matters," he added.

Kim is the youngest son of late President Kim Dae-jung known for his reconciliation drive toward the North. The Kaesong and Mount Kumgang projects were the most tangible fruits of the late president's "sunshine policy" of engaging Pyongyang.

South Korea closed the industrial park in the North's border town of Kaesong in 2016 in retaliation against the North's nuclear and missile provocations. Tours to Mount Kumgang on the North's east coast came to a halt in 2008 after a South Korean tourist was shot dead by a North Korean guard.

Seoul wants active economic cooperation with the North, including the resumption of the two symbolic cross-border projects, in the hope that it will deepen inter-Korean relations and set a positive tone for denuclearization talks between the North and the United States.

Economic cooperation with the North, however, has been blocked due to sanctions Washington vows to keep in place until the North's complete denuclearization that are aimed at preventing any hard currency from flowing into its weapons development programs.

Some have raised hopes that Seoul might have more leeway in pushing for cross-border cooperative projects following President Moon Jae-in's landmark three-way meeting with North Korean leader Kim Jong-un and US President Donald Trump in late June at the truce village of Panmunjom.

Kim of the KCRC said that the Panmunjom meeting has helped pave the way for the resumption of talks between the two Koreas but added the Seoul government has to play a "more active role" in advancing inter-Korean relations without making them subordinated to Washington-Pyongyang relations and future denuclearization talks. (Yonhap)